Beam or planar load cells, per se, are well known. They generally consist of a metal substrate with a semiconductor or metal foil bridge, such as a Wheatstone bridge circuit mounted on one surface of the substrate. In use, the deformation forces acting on the substrate are translated into a proportional change in electrical resistance at each of the four outputs of the Wheatstone bridge. This change in resistance is then used to obtain various types of information about the system in which the load cell is used. For example, load cells have found wide application in the measurement and tracking of continuous flow production processes wherein a change in flow rate translates into a corresponding change in the load cell output resistance which can then be output to a control device, such as a computer, that is used to appropriately adjust parameters to stabilize the process at the desired flow rates. However, load cells have generally not found wide applications in measurement of discrete events of short duration as the length of time needed by the load cell to produce a stable output signal, substantially free of resonant frequencies and noise, was longer than length of the event, the measurement of which was being attempted.
In view of the foregoing, it is, accordingly, an object of the present invention to provide a planar load cell that is capable of accurately measuring events of short duration.
Another object of the present invention is to provide a load cell that is substantially free of resonant frequencies and noise.
Still another object of the present invention is to provide a load cell that is inexpensive and easy to use.
Yet another object of the present invention is to provide a load cell that provides a stable output under conditions of varying temperature.